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Atrial fibrillation (AF) is associated with an increased risk of heart failure (HF), stroke, and death. Although fibrillation cycle length (FCL) is used as a surrogate for atrial refractoriness, its impact on outcomes remains unclear. This study aimed to identify predictors of cardiovascular events, including FCL, in patients with long-standing persistent AF. The study included 190 consecutive patients with long-standing persistent AF (mean age 74 years, 74% male). Patients with valvular AF or hemodialysis-dependent end-stage renal disease and those on anti-arrhythmic drugs were excluded. The primary composite outcome was occurrence of cardiovascular events (myocardial infarction, HF), cerebrovascular events (stroke, transient ischemic attack), and all-cause death. FCL was calculated by fast Fourier transformation analysis of fibrillation waves in the surface electrocardiogram. Over a median follow-up of 2.6 years, the primary outcome occurred in 31 patients (cardiovascular events, n = 18; cerebrovascular events, n = 8; all-cause death, n = 5). In multivariate analysis, longer FCL and history of HF were independent predictors of these outcomes. In a Cox proportional hazards model adjusted for age, sex, and history of HF, patients with an FCL > 160 ms (cut-off determined by receiver-operating characteristic curve analysis) were at increased risk of the outcome (hazard ratio 12.9; 95% confidence interval 4.99–44.10; p

Dipeptidyl peptidase 4 (DPP-4) inhibitors have recently been reported to exhibit additional cardioprotective effects; however, their effect in atrial remodeling, such as in atrial fibrillation (AF), remains unclear. In this study, the effect of linagliptin on atrial electrical and structural remodeling was evaluated in a canine AF model. Sixteen beagle dogs with 3-week atrial rapid stimulation were divided into the linagliptin group (9 mg/kg/day, n = 8) and pacing control group (n = 8). Three additional dogs without rapid pacing were assigned into non-pacing group, which was used as sham in this study. In the dogs with rapid pacing, the atrial effective refractory period (AERP), conduction velocity (CV), and AF inducibility were evaluated and blood was sampled every week. After the entire protocol, atrial tissue was sampled for histological examinations using HE, Azan, and dihydroethidium (DHE) staining to evaluate any tissue damage or oxidative stress. The pacing control group exhibited a gradual AERP shortening and CV decrease along the time course as previously reported. In the linagliptin group, the AERP shortening was not affected, but the CV decrease was suppressed in comparison to the control group (p

We have shown that a dipeptidyl peptidase 4 (DPP-4) inhibitor suppresses atrial remodeling in a canine atrial fibrillation (AF) model. Glucagon-like peptide-1 (GLP-1) is increased by DPP-4 inhibitors. However, it is not clear whether GLP-1 is involved in the suppression of atrial remodeling. In this study, we evaluated the effect of liraglutide (a GLP-1 analog) on atrial electrophysiological changes using the same canine AF model. We established a canine AF model using continuous 3-week rapid atrial stimulation in seven beagle dogs divided into two groups: a liraglutide group with four dogs (3-week atrial pacing with liraglutide (150 µg/kg/day) administration) and a pacing control group with three dogs (3-week pacing without any medicine). We evaluated the atrial effective refractory period (AERP), conduction velocity (CV), and AF inducibility every week during the protocol using implanted epicardial wires against the surfaces of both atria. In the pacing control group, the AERP was gradually shortened and the CV was decreased along the time course. In the liraglutide group, the AERP was similarly shortened as in the pacing control group (94 ± 4% versus 85 ± 2%, respectively; p = 0.5926), but the CV became significantly higher than that in the pacing control group after 2 and 3 weeks (95 ± 4 versus 83 ± 5%, respectively; p = 0.0339). The AF inducibility was gradually increased in the pacing control group, but it was suppressed in the liraglutide group (5 ± 9% versus 73 ± 5%; p = 0.0262). Liraglutide suppressed electrophysiological changes such as AF inducibility and CV decrease in our canine AF model.